This device relates to the field of devices for cleaning air filters by the use of forced air pressure, and more particularly relates to the field of such devices having a central air delivery system and means to retain and seal air filters within the device.
Air filters are used to prevent particulate impurities such as dust and dirt from entering into the combustion chambers of engines. A typical air filter has a filtering medium which allows for passage of air but traps the particulates on its outer surface. Filters are commonly annular with the filter medium incorporated into the cylindrical side wall. The air is drawn or forced through the filter from the outside to the inside. Additionally, filters may be square or rectangular in overall configuration, in which case the air is drawn in one side and exited out another after passing through the filtering medium.
Once the particulate build-up becomes significant, the ability of the filter to function properly is impaired and the filter may not allow sufficient air to enter the engine. In such cases, the filter either needs to be replaced or cleaned. If possible, it is preferable to clean the filter rather than replace it, both from a cost standpoint for the consumer and for the benefit of passing fewer discarded units into the waste stream, thereby reducing the land fill accumulation by hundreds of thousands of units.
In a typical service station setting, this cleaning is often performed by directing the air flow from a high pressure hose around the interior of the filter, or against the exit side of a square filter, to blow out the particulates massed on the external surface of the filter medium. This method is both ineffective and hazardous, as the filter can be easily damaged by the highly concentrated forced air. Therefore, devices have been developed to safely and easily clean filters. For example, Timian in U.S. Pat. No. 3,733,639 teaches a renovator device which uses a rotating air distributor mounted onto a vibrating plate. The components are contained in a cylindrical closed chamber and both a forced air source and a vacuum source are required. Likewise, Boylan in U.S. Pat. No. 4,492,003 teaches a cleaning unit utilizing forced air pressure. The Boylan device has a spring mounted deflector to direct the air outwardly in an even manner.
Both these devices suffer from the drawbacks of complexity in design and manufacture. Neither device can be used with a non-tubular air filter. It is an object of this invention to provide a simple air cleaning device which effectively distributes the air pressure around the entire inner surface of the tubular filter being cleaned. It is a further object to provide such a device which can also clean square or rectangular filters.